Why is FunctionList not running in different thread?browsing

I’m running NPP V6.9 and always if I’m switching between my big JavaScript project files FunctionList is reloaded, and I have to wait for it, until I can proceed with my work.
I’m wondering why FunctionList is not running in a different thread than UI.
Other editors like e.g. Geany are very fast with function listing with my same files…
Do you think it is possible to change that in future versions?